Garments for the outdoor athletic outerwear market can be divided into several main categories including hard shell, soft shell, and various types of laminated garments. In general, hard shell garments may be distinguished by the inclusion of a waterproofing barrier. Fleeces having a soft fabric generally of a knit construction are also used in the outerwear market, but these are not normally waterproof to the degree that hard shell garments are.
Because hard and soft shell garments are used during athletic and outdoor activities, it is desirable that they be light and rugged. For some applications, reducing the weight of the garment by even a small amount can be significant. In addition, from the manufacturer's point of view it is desirable that these garments be relatively simple to manufacture.
The method of joining pieces or panels of fabric to assemble a complete garment can be just as important to that garment's overall characteristics as the type of fabric used in that garment. While several prior-art methods exist for forming seams, each has its drawbacks. Simple conventional threaded stitching used alone, while common in the garment industry, is problematic because a completed stitch leaves a bulky seam in the otherwise lightweight fabric of the garment. Conventional threaded stitching typically requires lapped seams and/or a seam allowance of at least ⅛ of an inch. This requires additional fabric in the seam area and increases the weight and bulk of the garment. In waterproof garments, the passage of a needle through the fabric of the garment also compromises the waterproof nature of the fabric, necessitating the application of a seam tape secured with an adhesive over the stitched seam to ensure a waterproof seal.
However, gluing a length of seam tape over the stitched seam creates a new problem. Namely, a seam sewn in a traditional manner combined with tape tends to be rather stiff. The differential in stiffness between the taped seam formed by this process and the lightweight fabric joined by the sewn and taped seam leads to a phenomenon known as edge abrasion.
Because the region of the seam is much bulkier than the fabric panel which it joins, it causes a region of wear to build up just at the point where the fabric panel meets the taped seam. The continual flexing of the loose fabric against the stiff edge of the taped seam and any external abrasion causes the fabric to wear through at that point, reducing the life of an otherwise serviceable garment.
Alternatively, manufacturers have employed adhesives to join panels of fabric in a “stitchless” garment. Typically, what is known as a lap seam is made when two pieces of fabric are precut and overlapped. The pieces are secured with an adhesive applied in the area of overlap, which in some instances may require heating to fully interlock with the fibers of the fabric pieces.
However, the fabrics used in hard shell garments are usually either very tightly woven and/or have a durable water repellent (“DWR”) finish applied to the fabric surface to provide waterproofing for the fabric. A fair amount of adhesive must be applied to make a bond of sufficient strength with a fabric having such a weave or finish, making the overall seam that much stiffer once the adhesive has solidified. As such, this method of stitchless garment construction can create an even stiffer seam than that of the sewn and taped seam described above, and so garments constructed with this process can suffer from the problem of edge abrasion to an even greater degree. Also, some fabrics cannot be reliably bonded in this manner and can fail in use.
A composite seam system as described in co-pending U.S. patent application Ser. No. 10/906,392 titled “A Composite Seam System”, which is incorporated by reference herein in its entirety, overcomes some issues of the prior art by using an ultrasonically welded and taped seam. Although this composite seam system is suitable for some applications, it is not optimal for all types of fabrics and end uses. These types of seam systems are not optimal when using fleece, for example because it is difficult to adequately bond seaming tape to fleece fabrics when using only an ultrasonically welded seam for initial bonding. In applications that do not require waterproofing, the added bulk from seam tape is also not always desirable.
Accordingly, there is a need for a method of attaching fleece and other types of fabric to each other that results in a lightweight, non-bulky seam.